Prepare pasta according to package directions. Salt to taste.
Melt butter in a small saucepan. Whisk in flour to create a roux. Whisk in whole milk, raise heat to medium-high and cook until sauce thickens, stirring occasionally. Stir in ½ tsp salt.
Meanwhile, grate cheddar cheese. Once sauce thickens, stir in cheese. Combine pasta and sauce in an oven to table dish.
Bake for 30 minutes (more if you like crispy noodles, less if you’re in a rush and like it saucy).